I happen to come up with ideas like connecting tone cable to other 4 string instrument like cello. in fact, I  just tried to do it using piezo pickup and even though I can not tune my sister's cello to play ordinary guitar songs, I think this is possible if anyone make CDLC songs for the cello.     if there anyone tried to do something like this, plz share your experience.  I wonder that what kind of problem I will face, if i make one.